Received October 25, 2010; accepted December 3, 2010; published online January 15, 2011.
Full-text LinkOut at PubMed. Journal title in PubMed: Zhong Xi Yi Jie He Xue Bao.

Correspondence: Chen Wang, PhD, Associate Professor; Tel: 021-64385700-1427; E-mail: wangchen_longhua@yahoo.com.cn

     Pilonidal sinus is a complex condition that causes both discomfort and embarrassment to patients. It is diagnosed through identification of a characteristic epithelial track situated in the skin of the natal cleft, a short distance behind the anus and generally containing hairs^［1］. The onset of pilonidal sinus is most commonly seen between the age 15 and 40. The incidence in males is nearly ten times of that in females^［2］.

1  Case report
     A 29-year-old man with discharge and pain behind the anus was admitted to hospital. He had suffered from an abscess in the same place two month prior to treatment and underwent drainage. There were two openings between the buttocks at 8 cm and 2 cm posterior to the anus. Ultrasound revealed a 6-cm-long track between the two openings and a 3 cm×1.8 cm abscess overlying the coccyx. Magnetic resonance imaging (MRI) revealed no internal opening to the anal canal. Informed consent was obtained after full explanation of the procedure. He underwent thread-dragging therapy under spinal anaesthesia at left lateral position. One dose of metronidazole was used intravenously during the operation and three days afterwards. All the tracks and the abscess were curetted to remove epithelial and necrotic tissue. Tufts of hair were found during the operation. Incisions at the two openings and extension of the abscess were made for drainage. Ten silk threads were put through both incisions and knotted loosely. Once a day, post-surgery, part of the threads which were inside the tracks were dragged outside and cleaned with normal saline. After two weeks when the cavity became smaller due to the growth of granulation tissue and the threads could not be dragged easily, five threads were removed (Figure 1). Residual threads were removed when the tissue became fresh with no discharge at the 22nd day after surgery. At the same time, a cotton pad was wrapped with pressure over the wounds to accelerate healing of the cavity. All wounds were healed after 6 weeks and the patient was discharged then (Figure 2). Repeat ultrasound confirmed no track or abcess at natal cleft. The patient recovered well and has remained asymptomatic for 12 months now.

Figure 1  Thread-dragging therapy on pilonidal sinus at the 14th day after surgery

Figure 2  All wounds were healed after 6 weeks

2  Discussion
     The incidence of pilonidal sinus in China is low, but the recurrence and misdiagnosis are common^［3］. In this case we used ultrasound and MRI to confirm the diagnosis because location of the external openings and tracks were not like normal anal fistulae. To pilonidal sinus, depilation and local sterilization can be used at the chronic phase, but surgical management is suitable for complex and recurrent phases. The number and variety of published techniques are testament to the complexity of treating pilonidal sinus and the fact that no single procedure is superior in all respects^［4］. The aim of surgery is to remove the entire infected sinus and its ramification^［5］. Thread-dragging is one of the traditional Chinese medicine (TCM) therapies for complex fistula and abscess^［6］. In this case we used thread-dragging and pad pressure therapy to treat pilonidal sinus. It can protect the normal skin and subcutaneous tissues above the tracks or abscess cavity. Compared with the loose seton method, it not only has functions of marking and drainaging but also drains pus and necrotic tissues thoroughly. Appropriate pressure by a cotton pad can accelerate the tissue growth and adhesion as well. Compared with wide excision, rhomboid flap and skin grafting for pilonidal sinus, thread-dragging and pad pressure therapy is less invasive and involves smaller wound, shorter hospitalization, less pain and reduced scarring. Thus TCM thread-dragging and pad pressure therapy can be used as an alternative therapy for pilonidal sinus.